Electric switch.



No. 677,340. Patented'luly 2,- i901. A. GOWPERTHWAIT & n. o. LINDSTBOM.

. ELECTRIC SWITCH.

(Application filed Feb. 4, 1901.) (Ila Model.)

wnmgssazs: My INVENTORS %ZM W 721/ 4 llnirn Srnrns Pnrnnr ALLAN COYVPERTHXVAIT AND NILS O. LINDSTROM, OF NEW YORK, N. ASSIGNORS TO ALONZO 13. SEE AND W'ALTER L. TYLER, OF BROOKLYN,

NEW YORK.

ELECTRiC SWlTCH.

SEEQZFIQATION forming part'of Letters Patent No. 677,340, dated July 2, 1901.

Application filed February 4,1901. fierial No. 45,829. (No model.)

To all whont it may conceive.-

Be it known that we, ALLAN COWPER- THWAIT, residing in the city of New York, borough of Brooklyn, and NILS O. LINDSTROM, re-

siding in the city of New York, borough of Queens, State of New York, citizens of the United States, have invented certain new and useful Improvements in Electric Switches, of which the following is a full, clear, and exact description.

This invention relates to the contacts of electrical switches adapted to carry heavy currents and to that class of switches known as knife switches, in which a blade enters between a pair of yielding or spring-pressed contacts.

One object of the invention is to provide a construction of contacts which will insure of good and large surface contact between the coacting parts and to insure that the median line between the two spring-pressed contacts shall always be directly opposite the blade, so that the blade in moving into engagement with the contacts will strike exactly between them.

Another object of the invention is to provide carbon contacts which can be easily removed and replaced from the switch when necessary and will make good contact with the metallic parts when in position.

The invention consists of the details of construction hereinafter described and claimed. Referring to the accompanying drawings, Figure l is a side elevation of the improved switch contact, showing a portion of the switch-blade. Fig. 2 is a front elevation of the same, and Fig. 3 is a section on line co m of Fig. 1.

Referring to the drawings by letter, A represents a bracket consisting of two arms a, connected to the front of a plate a and joined together near their outer ends by a cross-piece a (Shown in dotted lines in Fig. 1.) This bracket is adapted to be secured to a slate or other suitable base. Between the arms of the bracket are pivoted two bell-crank levers b b, respectively, their pivots being horizontal and indicated at Z2 Each bellcrank has a long arm and a short arm, the 50 former being arranged substantially parallel to each other and the latter substantially in line with each other, but terminating a short distance apart. In the center of the crosspiece a ofthe bracket is secured a rod 0,

which extends midway between and parallel to the longer arms of the bell-cranks and at its extremity is provided with a nut c. The rod passes between the adjacent ends of the short arms of the bell-crank, they being slightly forked "to give the rod clearance. Upon the rod is placed a spiral spring oiwhich bears against the nut c at one end and against the extremities of both of the short arms of the bell-cranks, the spring being thereby held under compression and exerting an equal pressure on the levers to force the ends of the long arms toward each other.

At the extremity of each long'arm is fitted a tilting seat consisting of a rectangular plate 6, having flanges e at opposite sides or above and below, as shown, and having cars 6 through which pivot-pins 6 pass to secure the seats to the arms. In each of the seats is placed a carbon block f, having flanges f adapted to overlap the two sides of the seat which are not flanged, When the block is in place in the seat, it is prevented from moving in one direction by the flanges e on the seat and in the other direction by the flanges f on the block. The action of the spring 0 holds the two blocks in contact with each other or in contact with the blade, which is adapted to pass between them constantly, so that the blocks cannot by any possibility become nnseated. Yet when it is desired to remove either ;of the blocks for examination or substitution it is easily accomplished by simply separating the long arms of the levers and allowing the blocks to drop out. The pivot-pins 6 permit the blocks and seats to tilt or rock slightly, there being sufficient space between the back of the seats and the arms to permit this,for the purpose of making the blocks selfladjusting. In operation the blade of the switch (indicated by B) is caused to pass between the two carbon blocks, thus separating them and establishing contact therewith on the opposite sides of the blade. It will be seen that with a single spring acting thus uniformly upon both bell-cranks the junction between the two carbon blocks will always be in the same plane and directly opposite the Switchblade, so that in closing the switch the blade will go easily and smoothly to its seat between the blocks of carbon, and in opening the switch the blade will retreat from the blocks directly and avoid unnecessary sparking.

lVhen the carbon blocks and seats are constructed in the manner described, a good contact between the block and seat can be insured by making smooth fiat surfaces between them.

Having described our invention, we claim 1. A switch-contact consisting of apair of bell-crank levers, a tilting contact-seat at the free end of each lever, a carbon block in each seat and means for yieldingly holding the blocks in contact with each other; a

2. A switch-contact consisting of a pair of bell-crank levers, a spring acting against adjacent ends of said levers to throw the other ends together and contact-surfaces on the abutting faces of said other ends, substantially as described.

3. A switch-contact consisting of a pair of bell-crank levers, having arms substantially parallel to each other, and other arms substantially in line and projecting toward each other, facing contacts on the parallel arms, a rod passing between the ends of the other arms, a nut on the end of said rod and a. spring on the rod inserted between the nut and the ends of said arms in line with each other.

In witness whereof we subscribe our signatures in presence of two witnesses.

ALLAN COWPERTHWAIT. NILS O. LINDSTROM.

\Vitnesses:

WM. A. ROSENBAUM, WALDO M. CHAPIN. 

